PHP Core Warning – yii\base\ErrorException

$_GET = [
    0 => 'site/news',
    'id' => 2,
    'n_cat_id' => 3,
    'l' => 'ru_RU',
];

$_SESSION = [
    '__flash' => [],
    'history' => [
        '/ru/osobie-predlozhenija/akcii-na-drugoj-tovar.html',
    ],
    'cart' => [],
];